/*
 * Copyright (C) 2013 Michal Podhradsky
 * Utah State University, http://aggieair.usu.edu/
 *
 * This file is part of paparazzi.
 *
 * paparazzi is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * paparazzi is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with paparazzi; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 /**
 * @file imu_um6.c
 *
 * Driver for CH Robotics UM6 IMU/AHRS subsystem
 *
 * Takes care of configuration of the IMU, communication and parsing
 * the received packets. See UM6 datasheet for configuration options.
 * Should be used with ahrs_extern_euler AHRS subsystem.
 *
 * @author Michal Podhradsky <michal.podhradsky@aggiemail.usu.edu>
 */
#include "subsystems/imu/imu_um6.h"
#include "subsystems/imu.h"
#include "mcu_periph/sys_time.h"

struct UM6Packet UM6_packet;
uint8_t buf_out[IMU_UM6_BUFFER_LENGTH];
uint16_t data_chk;

uint8_t PacketLength;
uint8_t PacketType;
uint8_t PacketAddr;
enum UM6Status UM6_status;

uint16_t chk_calc;
uint16_t chk_rec;

struct FloatVect3 UM6_accel;
struct FloatRates UM6_rate;
struct FloatVect3 UM6_mag;
struct FloatEulers UM6_eulers;
struct FloatQuat UM6_quat;

inline void UM6_imu_align(void);
inline void UM6_send_packet(uint8_t *packet_buffer, uint8_t packet_length);
inline uint16_t UM6_calculate_checksum(uint8_t packet_buffer[], uint8_t packet_length);
inline bool_t UM6_verify_chk(uint8_t packet_buffer[], uint8_t packet_length);

inline bool_t UM6_verify_chk(uint8_t packet_buffer[], uint8_t packet_length) {
    chk_rec = (packet_buffer[packet_length-2] << 8) | packet_buffer[packet_length-1];
    chk_calc = UM6_calculate_checksum(packet_buffer, packet_length-2);
    return (chk_calc == chk_rec);
}

inline uint16_t UM6_calculate_checksum(uint8_t packet_buffer[], uint8_t packet_length) {
  uint16_t chk = 0;
  for (int i=0; i<packet_length; i++) {
    chk += packet_buffer[i];
  }
  return chk;
}

inline void UM6_send_packet(uint8_t *packet_buffer, uint8_t packet_length) {
  for (int i=0; i<packet_length; i++) {
    UM6Link(Transmit(packet_buffer[i]));
  }
}

void UM6_imu_align(void) {
    UM6_status = UM6Uninit;

    // Acceleration vector realign
    buf_out[0] = 's';
    buf_out[1] = 'n';
    buf_out[2] = 'p';
    buf_out[3] = 0;
    buf_out[4] = IMU_UM6_SET_MAG_REF;
    data_chk = UM6_calculate_checksum(buf_out, 5);
    buf_out[5] = (uint8_t)(data_chk >> 8);
    buf_out[6] = (uint8_t)data_chk;
    UM6_send_packet(buf_out, 7);

    // Magnetic realign
    buf_out[0] = 's';
    buf_out[1] = 'n';
    buf_out[2] = 'p';
    buf_out[3] = 0;
    buf_out[4] = IMU_UM6_SET_ACCEL_REF;
    data_chk = UM6_calculate_checksum(buf_out, 5);
    buf_out[5] = (uint8_t)(data_chk >> 8);
    buf_out[6] = (uint8_t)data_chk;
    UM6_send_packet(buf_out, 7);

    // Zero gyros 0xAC, takes around 3s
    buf_out[0] = 's';
    buf_out[1] = 'n';
    buf_out[2] = 'p';
    buf_out[3] = 0;
    buf_out[4] = IMU_UM6_ZERO_GYROS_CMD;
    data_chk = UM6_calculate_checksum(buf_out, 5);
    buf_out[5] = (uint8_t)(data_chk >> 8);
    buf_out[6] = (uint8_t)data_chk;
    UM6_send_packet(buf_out, 7);

    // Reset EKF 0xAD
    buf_out[0] = 's';
    buf_out[1] = 'n';
    buf_out[2] = 'p';
    buf_out[3] = 0;
    buf_out[4] = IMU_UM6_RESET_EKF_CMD;
    data_chk = UM6_calculate_checksum(buf_out, 5);
    buf_out[5] = (uint8_t)(data_chk >> 8);
    buf_out[6] = (uint8_t)data_chk;
    UM6_send_packet(buf_out, 7);

    UM6_status = UM6Running;
}

void imu_impl_init(void) {
  // Initialize variables
  UM6_status = UM6Uninit;

  // Initialize packet
  UM6_packet.status = UM6PacketWaiting;
  UM6_packet.msg_idx = 0;
  UM6_packet.msg_available = FALSE;
  UM6_packet.chksm_error = 0;
  UM6_packet.hdr_error = 0;

  // Communication register 0x00
  buf_out[0] = 's';
  buf_out[1] = 'n';
  buf_out[2] = 'p';
  buf_out[3] = 0x80;        // has data, zeros
  buf_out[4] = IMU_UM6_COMMUNICATION_REG;        // communication register address
  buf_out[5] = 0b01000110;  // B3 - broadcast enabled, processed data enabled (acc, gyro, mag)
  buf_out[6] = 0b10000000;  // B2 - no euler angles, quaternions enabled
  buf_out[7] = 0b00101101;  // B1 - baud 115200
  buf_out[8] = 100;        // B0 - broadcast rate, 1=20Hz, 100=130Hz, 255=300Hz
  data_chk = UM6_calculate_checksum(buf_out, 9);
  buf_out[9] = (uint8_t)(data_chk >> 8);
  buf_out[10] = (uint8_t)data_chk;
  UM6_send_packet(buf_out, 11);

  // Config register 0x01
  buf_out[0] = 's';
  buf_out[1] = 'n';
  buf_out[2] = 'p';
  buf_out[3] = 0x80;        // has data, zeros
  buf_out[4] = IMU_UM6_MISC_CONFIG_REG;  // config register address
  buf_out[5] = 0b11110000;  // B3 - mag, accel updates enabled, use quaternions
  buf_out[6] = 0;  // B2 - RES
  buf_out[7] = 0;  // B1 - RES
  buf_out[8] = 0;        // B0 - RES
  data_chk = UM6_calculate_checksum(buf_out, 9);
  buf_out[9] = (uint8_t)(data_chk >> 8);
  buf_out[10] = (uint8_t)data_chk;
  UM6_send_packet(buf_out, 11);

  /*
  // Get firmware
  buf_out[0] = 's';
  buf_out[1] = 'n';
  buf_out[2] = 'p';
  buf_out[3] = 0;
  buf_out[4] = IMU_UM6_GET_FIRMWARE_CMD;
  data_chk = UM6_calculate_checksum(buf_out, 5);
  buf_out[5] = (uint8_t)(data_chk >> 8);
  buf_out[6] = (uint8_t)data_chk;
  UM6_send_packet(buf_out, 7);
  */

  UM6_imu_align();
}



void imu_periodic(void) {
  /* We would request for data here - optional
  //GET_DATA command 0xAE
  buf_out[0] = 's';
  buf_out[1] = 'n';
  buf_out[2] = 'p';
  buf_out[3] = 0;           // zeros
  buf_out[4] = 0xAE;        // GET_DATA command
  data_chk = UM6_calculate_checksum(buf_out, 5);
  buf_out[5] = (uint8_t)(data_chk >> 8);
  buf_out[6] = (uint8_t)data_chk;
  UM6_send_packet(buf_out, 7);
  */
}

void UM6_packet_read_message(void) {
  if ((UM6_status == UM6Running) && PacketLength > 11) {
      switch (PacketAddr) {
        case IMU_UM6_GYRO_PROC:
           UM6_rate.p =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+0]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+1])))*0.0610352;
           UM6_rate.q =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+2]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+3])))*0.0610352;
           UM6_rate.r =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+4]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+5])))*0.0610352;
           RATES_SMUL(UM6_rate, UM6_rate, 0.0174532925); //Convert deg/sec to rad/sec
           RATES_BFP_OF_REAL(imu.gyro, UM6_rate);
           break;
        case IMU_UM6_ACCEL_PROC:
           UM6_accel.x =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+0]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+1])))*0.000183105;
           UM6_accel.y =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+2]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+3])))*0.000183105;
           UM6_accel.z =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+4]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+5])))*0.000183105;
          VECT3_SMUL(UM6_accel, UM6_accel, 9.80665); //Convert g into m/s2
          ACCELS_BFP_OF_REAL(imu.accel, UM6_accel); // float to int
           break;
        case IMU_UM6_MAG_PROC:
           UM6_mag.x =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+0]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+1])))*0.000305176;
           UM6_mag.y =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+2]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+3])))*0.000305176;
           UM6_mag.z =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+4]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+5])))*0.000305176;
           // Assume the same units for magnetic field
           // Magnitude at the Earth's surface ranges from 25 to 65 microteslas (0.25 to 0.65 gauss).
           MAGS_BFP_OF_REAL(imu.mag, UM6_mag);
           break;
        case IMU_UM6_EULER:
           UM6_eulers.phi =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+0]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+1])))*0.0109863;
           UM6_eulers.theta =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+2]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+3])))*0.0109863;
           UM6_eulers.psi =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+4]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+5])))*0.0109863;
           EULERS_SMUL(UM6_eulers,UM6_eulers, 0.0174532925); //Convert deg to rad
           EULERS_BFP_OF_REAL(ahrs_impl.ltp_to_imu_euler, UM6_eulers);
           break;
        case IMU_UM6_QUAT:
           UM6_quat.qi =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+0]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+1])))*0.0000335693;
           UM6_quat.qx =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+2]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+3])))*0.0000335693;
           UM6_quat.qy =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+4]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+5])))*0.0000335693;
           UM6_quat.qz =
                    ((float)((int16_t)
                    ((UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+6]<<8)|UM6_packet.msg_buf[IMU_UM6_DATA_OFFSET+7])))*0.0000335693;
           QUAT_BFP_OF_REAL(ahrs_impl.ltp_to_imu_quat, UM6_quat);
           break;
        default:
          break;
      }
  }
}

/* UM6 Packet Collection */
void UM6_packet_parse( uint8_t c ) {
 switch (UM6_packet.status) {
  case UM6PacketWaiting:
    UM6_packet.msg_idx = 0;
    if (c == 's') {
      UM6_packet.status = UM6PacketReadingS;
      UM6_packet.msg_buf[UM6_packet.msg_idx] = c;
      UM6_packet.msg_idx++;
    } else {
      UM6_packet.hdr_error++;
      UM6_packet.status = UM6PacketWaiting;
    }
    break;
  case UM6PacketReadingS:
    if (c == 'n') {
      UM6_packet.status = UM6PacketReadingN;
      UM6_packet.msg_buf[UM6_packet.msg_idx] = c;
      UM6_packet.msg_idx++;
    } else {
      UM6_packet.hdr_error++;
      UM6_packet.status = UM6PacketWaiting;
    }
    break;
  case UM6PacketReadingN:
    if (c == 'p') {
      UM6_packet.status = UM6PacketReadingPT;
      UM6_packet.msg_buf[UM6_packet.msg_idx] = c;
      UM6_packet.msg_idx++;
    } else {
      UM6_packet.hdr_error++;
      UM6_packet.status = UM6PacketWaiting;
    }
    break;
  case UM6PacketReadingPT:
    PacketType = c;
    UM6_packet.msg_buf[UM6_packet.msg_idx] =  c;
    UM6_packet.msg_idx++;
    UM6_packet.status = UM6PacketReadingAddr;
    if ((PacketType & 0xC0) == 0xC0) {
      PacketLength = 4*((PacketType >>2) & 0xF) + 7; // Batch, has 4*BatchLength bytes of data
    }
    else if ((PacketType & 0xC0) == 0x80) {
      PacketLength = 11; // Not batch, has 4 bytes of data
    }
    else if ((PacketType & 0xC0) == 0x00) {
      PacketLength = 7; // Not batch, no data
    }
    break;
  case UM6PacketReadingAddr:
    PacketAddr = c;
    UM6_packet.msg_buf[UM6_packet.msg_idx] =  c;
    UM6_packet.msg_idx++;
    UM6_packet.status = UM6PacketReadingData;
    break;
  case UM6PacketReadingData:
    UM6_packet.msg_buf[UM6_packet.msg_idx] =  c;
    UM6_packet.msg_idx++;
    if (UM6_packet.msg_idx == PacketLength) {
      if (UM6_verify_chk(UM6_packet.msg_buf, PacketLength)) {
        UM6_packet.msg_available = TRUE;
      } else {
        UM6_packet.msg_available = FALSE;
        UM6_packet.chksm_error++;
      }
    UM6_packet.status = UM6PacketWaiting;
    }
    break;
  default:
    UM6_packet.status = UM6PacketWaiting;
    UM6_packet.msg_idx = 0;
    break;
  }
}
